The objective of the proposed investigations is to gain a better understanding of phagocytic cell function in normals and in patients with hematologic disorders. We plan to elucidate the events that are responsible for the activation activity and inactivation of the oxidase system that is involved in the bacteriocidal and tumoricidal activity of phagocytic cells. We will examine ligand binding, calcium translocation, membrane depolarization, membrane fluidity, whole cell superoxide production and activity of the NAD(P)H oxidase responsible for it. We will also examine the ontogeny of the oxidase and myeloperoxidase responsible for it. We will also examine the ontogeny of the oxidase and myeloperoxidase and the role of oxidative metabolism in the monoclonal antibody dependent cell mediated cytotoxicity of lymphoid cells and tumor cells. We will also attempt to label and isolate the NAD(P)H oxidase system using a photoaffinity labelled FAD. These studies in normal and deficient cells will help define the biochemical and biophysical events necessary for phagocytic cells to function.